U.S. patent application number 10/830069 was filed with the patent office on 2004-10-07 for compositions, methods for producing films, functional elements, methods for producing functional elements, methods for producing electro-optical devices and methods for producing electronic apparatus.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Endo, Ayae, Morii, Katsuyuki, Seki, Shunichi.
Application Number | 20040195551 10/830069 |
Document ID | / |
Family ID | 18927382 |
Filed Date | 2004-10-07 |
United States Patent
Application |
20040195551 |
Kind Code |
A1 |
Endo, Ayae ; et al. |
October 7, 2004 |
Compositions, methods for producing films, functional elements,
methods for producing functional elements, methods for producing
electro-optical devices and methods for producing electronic
apparatus
Abstract
In accordance with the invention, a composition including a
solvent and a functional material is prepared. The solvent includes
at least one heterocyclic compound having one or more substituents
and containing an oxygen atom as a constituent atom. The functional
material is selected from a group including organic EL materials,
conductive materials, insulative materials and semiconductive
materials. Functional films and functional elements are prepared by
using the composition.
Inventors: |
Endo, Ayae; (Suwa-gun,
JP) ; Seki, Shunichi; (Suwa-gun, JP) ; Morii,
Katsuyuki; (Suwa-gun, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
18927382 |
Appl. No.: |
10/830069 |
Filed: |
April 23, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10830069 |
Apr 23, 2004 |
|
|
|
10095048 |
Mar 12, 2002 |
|
|
|
Current U.S.
Class: |
252/500 |
Current CPC
Class: |
H01L 51/0053 20130101;
H01L 51/0039 20130101; H01L 51/0007 20130101; H01L 51/0059
20130101; H01L 51/0034 20130101; H01L 51/0036 20130101; H01L
51/0043 20130101; H01L 51/0004 20130101; H01L 51/0005 20130101;
H01L 51/0035 20130101; H01L 51/5012 20130101 |
Class at
Publication: |
252/500 |
International
Class: |
H01B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2001 |
JP |
2001-069337 |
Claims
What is claimed is:
1. A method for producing a film, comprising: applying a
composition with a discharge device to form said film, wherein said
composition comprises a solvent including at least one heterocyclic
compound having one or more substituents and containing an oxygen
atom as a constituent atom; and a functional material selected from
a group including conductive materials, insulative materials and
semiconductive materials.
2. The method for producing a film according to claim 1, further
including utilizing an ink-jet device as the discharge device.
3. The method for producing a film according to claim 1, further
including applying the composition onto a substrate, and subjecting
the substrate carrying the composition to heat treatment and/or
pressurization or pressure reduction.
4. The method for producing a film according to claim 1, said
composition including a functional material selected from a group
including conductive materials, insulative materials and
semiconductive materials.
5. The method for producing a film according to claim 4, said
functional material including at least an organic
electro-luminescence materials.
6. The method for producing a film according to claim 1, said
heterocyclic compound having a boiling point of equal to or more
than 170.degree. C.
7. The method for producing a film according to claim 1, said
heterocyclic compound having a furan materials.
8. The method for producing a film according to claim 1, said
heterocyclic compound being 2,3-dihydrodenzofuran.
9. The method for producing a film according to claim 1, said
solvent including said heterocyclic compound that further includes
another organic solvent.
10. The method for producing a film according to claim 9, said
solvent including said heterocyclic compound that includes a
benzene derivative.
Description
[0001] This is a Division of Application No. 10/095,048 filed Mar.
12, 2002. The entire disclosure of the prior application is hereby
incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to a composition (a discharge
composition) that can be used for the formation of thin films of
functional materials, especially for the formation of patterned
films of functional materials using discharge devices, and that can
stably be discharged. The invention also relates to a method for
producing a uniform film (a functional film) using the composition,
to a functional element, to a method for producing the functional
element, to a method for producing an electro-optical device and to
a method for producing electronic apparatus.
[0004] 2. Description of Related Art
[0005] Thin films can be produced from liquid phases by a wide
variety of processes, such as by a spin coating process, a sol-gel
process and a blade process. According to these processes, a
composition containing a material, as a solute that is dissolved or
dispersed in a solvent, is applied to a substrate, and the solvent
is removed, for example, by heating, to thereby yield a functional
thin film.
[0006] Such functional materials have conventionally been patterned
by a photolithography process in many cases. However, the
photolithography process is subject to disadvantages, such as high
cost, complicated steps and large amounts of materials consumed.
Accordingly, fine patterning techniques of functional materials
using discharge devices, especially using ink-jet printing devices,
have been examined, since such discharge devices entail low costs
and simple steps. Examples of products of fine patterning of
functional materials using ink-jet printing devices include: color
filters (Japanese Unexamined Patent Application Publications No.
9-329706 and No. 11-202114) and organic EL display devices
(Japanese Unexamined Patent Application Publications No. 7-235378,
No. 10-12377 and No. 10-153967). As such discharge compositions, a
composition for organic EL elements for easily patterning a thin
film in a short time with high precision and for easily optimizing
a film design and light-emitting characteristics is disclosed in
Japanese Unexamined Patent Application Publication No. 11-40358,
and a discharge composition for easy and precise pattering in a
short time without curving of the discharged composition or
clogging is disclosed in Japanese Unexamined Patent Application
Publication No. 11-54270.
SUMMARY OF THE INVENTION
[0007] The present invention provides a composition including a
solvent and a functional material. The solvent includes at least
one heterocyclic compound having one or more substituents and
containing an oxygen atom as a constituent atom. The functional
material is selected from the group including organic EL materials,
conductive materials, insulative materials and semiconductive
materials.
[0008] The present invention also provides a method for producing a
film. This method includes the step of applying the composition as
a pattern to thereby form a thin film.
[0009] The present invention also provides a method for producing a
functional element. This method includes the step of forming the
functional thin film.
[0010] The present invention further provides a functional element
that is made from the composition.
[0011] The present invention provides a method for producing an
electro-optical device. This method includes the step of forming a
functional thin film according to the aforementioned method.
[0012] In addition, the present invention provides a method for
producing electronic apparatus. This method includes the step of
forming a functional thin film according to the aforementioned
method.
[0013] The patterning process using discharge devices, especially
using ink-jet printing devices, does not require any plate making,
can save resources, can save labor and has very satisfactory
characteristics, but is subject to the disadvantage that materials
for use in discharge compositions are limited, as mentioned
below.
[0014] First, some of nonpolar or less polar functional materials
or polymeric materials are insoluble or slightly soluble in
solvents, such as water or alcohols, used in the ink-jet process,
and solvents, such as water or alcohols, cannot be used in
functional materials that are reactive with, or decomposed by,
these solvents.
[0015] Second, when a material having low solubility in the solvent
is used, a solution having an optimal concentration for film
formation induces an ingredient to be precipitated after the
preparation of the composition or causes clogging upon discharge.
In contrast, when a solution having a low concentration is used to
avoid clogging upon discharge, the number of discharge procedures
of the composition must be increased to thereby increase the number
of steps in order to prepare a functional film having a sufficient
film thickness so as to exhibit the characteristics of the
functional material.
[0016] Third, when an organic solvent having a high vapor pressure
is used as the solvent in the functional material, evaporation of
the solvent deprives the discharge composition of vaporization heat
to thereby accelerate deposition of the functional material upon
discharge or during film formation after discharge. Thus, the
solvent is evaporable, and thereby induces deposition and clogging
of the functional material. When the functional material is a
multicomponent system, the resulting film induces phase separation,
becomes heterogeneous and thereby loses its functions as the
functional film.
[0017] Fourth, the resulting thin film formed by the ink-jet
process may exhibit an irregular film thickness, such as a thin
center and thick periphery, during drying procedure after
application of the composition, and the film thickness cannot
significantly be controlled.
[0018] Accordingly, the present invention provides a composition
that can use nonpolar or less polar functional materials,
functional materials reactive with solvents, such as water or
alcohols, or polymeric materials in the formation of thin films of
such functional materials, especially in the formation of patterned
films of the functional materials using discharge devices. The
present invention also provides a composition that can stably be
discharged without clogging upon discharge or curving of the
discharged composition in the application of the composition by the
ink-jet process. The present invention also provides a method for
producing a film, which method can produce a uniform and homogenous
thin film using the composition, a functional element, especially
an organic EL element, and a method for producing the same, as well
as to provide methods for producing an electro-optical device and
electronic apparatus that each have the functional element, and
specifically to provide an organic EL display device having the
functional element.
[0019] The composition (especially a liquid composition) in
accordance with an embodiment of the present invention includes a
solvent and a functional material. The solvent includes at least
one heterocyclic compound having one or more substituents and
containing an oxygen atom as a constituent atom, and the functional
material is selected from the group including organic EL materials,
conductive materials, insulative materials and semiconductive
materials.
[0020] The composition has the following advantages. Specifically,
functional materials for use in the composition are not
specifically limited, and nonpolar or less polar materials or
reactive materials that are susceptible to reactions with water can
be used without deteriorating their functions. In addition, the
resulting composition can prevent or reduce, due to high solubility
of constitutive materials, deposition of ingredients after the
preparation of the composition or clogging upon discharge in the
ink-jet process.
[0021] The heterocyclic compound in the composition preferably has
a furan skeleton. By this configuration, the resulting composition
can prevent or reduce, due to high solubility of constitutive
materials, deposition of ingredients after the preparation of the
composition or clogging upon discharge and can stably be discharged
in the ink-jet process.
[0022] The heterocyclic compound in the composition preferably has
a boiling point of equal to or more than 170.degree. C. By this
configuration, the resulting composition can prevent or reduce
deposition of the solute after the preparation of the composition
or clogging upon discharge due to evaporation of the solvent and
can stably be discharged.
[0023] The heterocyclic compound in the composition is preferably
2,3-dihydrobenzofuran. This configuration has an advantage in that
functional materials for use in the composition are not
specifically limited, and that nonpolar or less polar materials or
reactive materials that are susceptible to reactions with water can
be used without deteriorating their functions. In addition, the
resulting composition can prevent or reduce, due to high solubility
of constitutive materials, deposition of ingredients after the
preparation of the composition or clogging upon discharge and can
stably be discharged in the ink-jet process.
[0024] In the composition, the solvent that includes at least the
oxygen heterocyclic compound preferably further includes another
organic solvent. By this configuration, the resulting composition
can prevent or reduce deposition of ingredients after the
preparation of the composition or clogging upon discharge due to
evaporation of the solvent and can stably be discharged. This
composition also has an advantage in that the composition can have
a controlled viscosity appropriate for the application, and the
target functional film can easily be designed.
[0025] The composition that includes the other solvent preferably
includes a benzene derivative as the other solvent. By this
configuration, the resulting composition can prevent or reduce
deposition of ingredients after the preparation of the composition
or clogging upon discharge due to evaporation of the solvent and
can stably be discharged. This composition also has an advantage in
that the composition can have a controlled viscosity appropriate
for the application, and the target functional film can easily be
designed.
[0026] The method for producing a film in accordance with another
embodiment of the present invention includes the step of applying
the composition as a pattern to thereby form a thin film. This
production method can prevent or reduce irregular film thicknesses
during drying procedure after the application of the composition
and phase separation of ingredients, and can yield uniform and
homogeneous functional films.
[0027] In the method for producing a film, the composition is
preferably applied with a discharge device. This configuration can
easily yield finely patterned functional films at low costs.
[0028] The discharge device in the production method just mentioned
above is preferably an ink-jet device. This configuration can
easily yield finely patterned functional films at low costs without
plate making.
[0029] In the method for producing a film, it is preferred that the
composition is applied onto a substrate, and the substrate carrying
the composition is subjected to heat treatment and/or
pressurization or pressure reduction. This configuration can
prevent or reduce irregular film thickness and phase separation of
ingredients, and can yield uniform and homogeneous functional
films.
[0030] The method for producing a functional element in accordance
with yet another embodiment of the present invention includes the
step of forming the functional thin film.
[0031] In the method for producing a functional element, a film
that includes an organic EL material is preferably formed as the
functional thin film.
[0032] The functional element in accordance with another embodiment
of the present invention is made from the composition.
[0033] The functional element is preferably an organic EL
element.
[0034] The method for producing an electro-optical device in
accordance with yet another embodiment of the present invention
includes the step of forming the functional thin film. Such an
electro-optical device is specifically preferably an organic EL
display device.
[0035] In addition, the method for producing electronic apparatus
in accordance with a further embodiment according to the present
invention includes the step of forming the functional thin
film.
[0036] The composition provided by the present invention is a
composition for use in the formation of patterned films of
functional materials and includes a solvent and a functional
material. The solvent includes at least one heterocyclic compound
having one or more substituents and containing an oxygen atom as a
constituent atom, and the functional material is selected from the
group including conductive materials, insulative materials and
semiconductive materials.
[0037] Functional materials for use in the composition are not
specifically limited, and nonpolar or less polar materials or
reactive materials that are susceptible to reactions with water can
be used. Such functional materials include materials corresponding
to the use of the composition of the present invention, such as
organic EL (electroluminescence) materials and other light-emitting
materials, organometallic compounds and other conductive materials,
dielectric or semiconductive materials. Among these materials,
organic EL materials are preferred.
[0038] The composition provided by the present invention is used
for the formation of thin films of functional materials, especially
for the formation of patterned films of such functional materials
using discharge devices.
[0039] Solvents that each include at least one heterocyclic
compound having one or more substituents and including an oxygen
atom as a constituent atom are preferably used as the solvent for
use in such a composition that includes the material as a solute
and is stable after preparation of the composition and during
application procedure of the composition. More preferably, the
heterocyclic compound has a furan skeleton.
[0040] Such heterocyclic compounds may be either monocyclic
heterocyclic compounds or condensed heterocyclic compounds. They
may be heterocyclic compounds that each include a hetero atom, such
as oxygen atom, nitrogen atom or a sulfur atom, and having two or
more carbon atoms.
[0041] The substituents are not specifically limited and include,
for example, straight- or branched-chain aliphatic hydrocarbon
groups, alicyclic hydrocarbon groups and aromatic hydrocarbon
groups.
[0042] Examples of such heterocyclic compounds are tetrahydrofuran,
furan, oxazole, isoxazole, furazane, benzofuran,
2,3-dihydrobenzofuran, 1,2-benzisoxazole and
2-methylbenzoxazole.
[0043] The solvent may be a single solvent including one of the
heterocyclic compounds, or a mixed solvent including two types or
more of the heterocyclic compounds. Alternatively, the solvent may
be a mixture including the heterocyclic compound and another
solvent other than the heterocyclic compound. Benzene derivatives
are preferred as the solvent other than the heterocyclic compound.
Examples of such benzene derivatives are cymene, tetralin, cumene,
decalin, durene, cyclohexylbenzene, dihexylbenzenes,
tetramethylbenzenes and dibutylbenzenes. By using these solvents,
the composition can have a controlled viscosity that is appropriate
for the application, and the target functional film can easily be
designed.
[0044] The aforementioned composition includes highly soluble
materials, and can therefore prevent or reduce deposition of
ingredients after the preparation of the composition. A solvent for
use in the formation of a patterned film of a functional material
using the ink-jet process preferably has high solvency for the
functional material, and has a high boiling point and/or a low
vapor pressure to prevent clogging upon discharge or curving of the
discharged composition due to evaporation of the solvent or
deposition of ingredients and to stably be discharged. Such a
solvent more preferably has a boiling point of equal to or more
than 170.degree. C., and a vapor pressure at room temperature of
from 0.10 to 10 mm-Hg.
[0045] Any process such as a spin coating process, a dipping
process, a casting process and a blade process can be applied to
the method for producing a thin film using the composition.
[0046] Processes using discharge devices are typically preferred as
a process for fine patterning of a functional material for their
low costs and simple steps. Among these processes, the ink-jet
printing process is specifically preferred.
[0047] The target functional film is prepared according to a
technique, such as air-drying, heating, pressurization or pressure
reduction, gas-flow drying, or combinations of these techniques,
during or after the application of the composition onto the
substrate.
[0048] The above production method can yield a uniform and
homogenous functional film without irregular film thickness or
phase separation of ingredients. By using procedures to remove the
solvent in combination, the target functional film can easily be
designed.
[0049] The functional element can yield a colored organic EL
element when the ink-jet process is employed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] FIG. 1 is a schematic of a planar structure of an example of
an organic EL panel as an electro-optical device;
[0051] FIG. 2 is a sectional view showing a structure of a
substrate used in an example according to the present
invention;
[0052] FIG. 3 is a sectional view showing a step of a method for
producing an organic EL element of the example according to the
present invention;
[0053] FIG. 4 is a sectional view showing another step of the
method for producing an organic EL element of the example according
to the present invention;
[0054] FIG. 5 is a sectional view showing another step of the
method for producing an organic EL element of the example according
to the present invention;
[0055] FIG. 6 is a sectional view showing another step of the
method for producing an organic EL element of the example according
to the present invention;
[0056] FIG. 7 is a sectional view showing another step of the
method for producing an organic EL element of the example according
to the present invention;
[0057] FIG. 8 is a sectional view schematically showing a
cross-section of a light-emitting layer of an organic EL element
obtained in the example according to the present invention;
[0058] FIG. 9 is a sectional view schematically showing a
cross-section of a light-emitting layer of an organic EL element
obtained as a comparative example with respect to the example
according to the present invention;
[0059] FIG. 10 is a graph showing voltage-luminance characteristics
of the organic EL elements obtained as a comparative example and
the example according to the present invention;
[0060] FIG. 11 is a graph showing voltage-current characteristics
of the organic EL elements obtained as a comparative example and
the example according to the present invention;
[0061] FIGS. 12(a)-12(c) are perspective views of examples of
electronic apparatus using organic EL panels, in which FIG. 12(a)
is a perspective view showing an example in which the organic EL
panel is applied to a mobile phone; FIG. 12(b) is a perspective
view showing an example in which the organic EL panel is applied to
an information processing device; and FIG. 12(c) is a perspective
view showing an example in which the organic EL panel is applied to
wristwatch-type electronic apparatus.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0062] The present invention will be illustrated in further detail
with reference to several embodiments below in accordance with
exemplary organic EL elements, which are not intended to limit the
scope of the invention.
EXAMPLE 1
[0063] A composition (G1) (solution) indicated in Table 1 was
prepared as a composition for a green light-emitting layer.
[0064] A composition (B1) (solution) indicated in Table 2 was
prepared as a composition for a blue light-emitting layer.
[0065] A composition (R1) (solution) indicated in Table 3 was
prepared as a composition for a red light-emitting layer.
1TABLE 1 Light-emitting Layer (Green) Composition Composition
Material Compositional Amount Light-emitting layer Compound 1 0.76
g material Compound 2 0.20 g Compound 3 0.04 g Solvent
2,3-Dihydrobenzofuran 60 ml Cyclohexylbenzene 40 ml
[0066]
2TABLE 2 Light-emitting Layer (Blue) Composition Composition
Material Compositional Amount Light-emitting layer Compound 1 0.78
g material Compound 2 0.25 g Compound 4 0.07 g Solvent
2,3-Dihydrobenzofuran 60 ml Cyclohexylbenzene 40 ml
[0067]
3TABLE 3 Light-emitting Layer (Red) Composition Composition
Material Compositional Amount Light-emitting layer Compound 1 0.70
g material Compound 2 0.20 g Compound 5 0.10 g Solvent
2,3-Dihydrobenzofuran 60 ml Cyclohexylbenzene 40 ml
[0068] The structures of Compounds 1 through 5 used in the
compositions are shown below. 1
[0069] As comparative examples, light-emitting layer compositions
(G2), (B2) and (R2) (each a solution) were prepared in the same
formulae as in Tables 1 through 3, except that they contain no
2,3-dihydrobenzofuran.
[0070] The compositions were stored at room temperature for one
month, and then changes in turbidity at 650 nm were checked on the
green and blue light-emitting compositions, and changes in
turbidity (changes in turbidity with respect to the turbidity of
the composition immediately after preparation) at 700 nm were
checked on the red light-emitting compositions.
[0071] Table 4 shows comparisons of stability of the
compositions.
4TABLE 4 Stability of Compositions One Composition week later One
month later Green light-emitting composition G1 Good Good G2 Good
Poor Blue light-emitting composition B1 Good Good B2 Good Poor Red
light-emitting composition R1 Good Good R2 Good Poor Good: No
change in turbidity Poor: Change in turbidity
[0072] Compositions (G2), (B2) and (R2) were very stable within one
week after the preparation of the compositions, but showed
deposition of ingredients one month later. In contrast,
Compositions (G1), (B1) and (R1) were very stable, even one month
after the preparation of the compositions.
EXAMPLE 2
[0073] A hole injection-transportation composition (solution)
having a formula shown in Table 5 below was prepared.
5 Composition Material Name Content (wt. %) Hole injection- Baytron
P 11.08 transportation material Poly(styrene Sulfonate) 1.44 Polar
solvent Isopropyl alcohol 10 N-Methylpyrrolidone 27.48
1,3-Dimethyl-imidazolinone 50
[0074] The composition (solution) shown in Table 1 was prepared as
a green light-emitting layer composition.
[0075] Next, a method for producing an organic EL element by the
ink-jet process using these materials will be illustrated. In
advance of this, a schematic configuration of an example of an
organic EL panel will be illustrated as an electro-optical device
using the organic EL element as a functional element.
[0076] FIG. 1 is a schematic of a planar structure of an example of
such an organic EL panel as an electro-optical device, in which the
reference numeral 70 is an organic EL panel. The organic EL panel
70 includes a substrate 2, a plurality of organic EL elements and a
sealing substrate (not shown). The substrate 2 is made of, for
example, glass, and the organic EL elements constitute pixels 71
arrayed in a matrix form.
[0077] The substrate 2 includes a transparent substrate, such as
glass, and is partitioned into a display area 2a and a non-display
area 2b. The display area 2a is at the center of the substrate 2,
and the non-display area 2b is on the periphery of the substrate 2
and is arranged outside the display area 2a. The display area 2a is
an area formed by the organic EL elements arrayed in a matrix form,
and is also referred to as a qualified display area.
[0078] A circuit element unit (not shown) is formed between the
substrate and an organic EL element unit (not shown) including the
organic EL elements and a rib (not shown) and carries, for example,
thin film transistors to be scanning lines, signal lines, retention
volumes or switching elements.
[0079] Cathode wiring 12 is arranged on the periphery of the
substrate 2, i.e., in the non-display area 2b. The cathode wiring
12 leads to cathodes (counter electrodes) of the organic EL
elements constituting the pixels 71, and is connected to a wiring
5a on a flexible substrate 5 at its edge. The wiring 5a is
connected to a driver IC 6 (a driver circuit) formed on the
flexible substrate 5.
[0080] Power source wires 103 (103R, 103G and 103B) are wired to
the circuit element unit in the non-display area 2b.
[0081] A pair of scanning driver circuits 73 is arranged at both
sides of the display area 2a. These scanning driver circuits 73 are
formed in the aforementioned circuit element unit. Driver circuit
control signal wiring 73a and driver circuit power source wiring
73b are formed inside of the circuit element unit, and are
connected to the scanning driver circuits 73.
[0082] An inspection circuit 74 is arranged on one side of the
display area 2a. The quality and defects of the resulting display
device during production or upon shipping can be checked with the
inspection circuit 74.
[0083] A sealing unit (not shown) is formed on the organic EL
element unit to cover the same. The sealing unit includes a sealing
resin applied onto the substrate 2, and a can-sealing substrate (a
sealing substrate).
[0084] The process for producing organic EL elements as components
of such an organic EL panel will be illustrated below, with
reference to FIGS. 2 through 11.
[0085] Only one pixel is illustrated in this process, but these
pixels are arrayed with a pitch of 70.5 .mu.m, as shown in FIG. 2.
A multilayer structure including a polyimide film 13 and a SiO2
film 12 is formed on a glass substrate 10 carrying a patterned
lithium tin oxide (ITO) 11 by photolithography. The multilayer
structure has an opening diameter (opening diameter of the SiO2
layer) of 28 .mu.m and a height of 2 .mu.m. An aperture at the
topmost of the polyimide layer is 32 .mu.m. Before the application
of the hole injection-transportation composition, the substrate was
subjected to plasma treatment at atmospheric pressure, and thereby
the polyimide bank became ink-repellent. As the plasma treatment at
atmospheric pressure, the substrate was subjected to oxygen plasma
treatment at an oxygen gas flow rate of 80 ccm, a helium gas flow
rate of 10 SLM and a table transfer speed of 5 mm/s, and was then
subjected to CF4 plasma treatment at a CF4 gas flow rate of 100
ccm, a helium gas flow rate of 10 SLM and a table transfer speed of
3 mm/s. Both treatments were performed at atmospheric pressure at a
power of 300 W, and a distance between the electrode and the
substrate of 1 mm.
[0086] With reference to FIGS. 3 through 5, after the surface
treatment of the substrate, 15 pl of the hole
injection-transportation composition (solution) 15 having the
formula indicated in Table 5 was discharged from an ink-jet
printing device head 14 to apply the same as a pattern. The solvent
was then removed at room temperature in a vacuum (1 torr) for 20
minutes, followed by heat treatment at 200.degree. C. (on a hot
plate) in the air for 10 minutes to thereby yield a hole
injection-transportation layer 16.
[0087] Next, 20 pl of a green light-emitting layer composition 17
indicated in Table 1 was discharged from the ink-jet printing
device head 14 to be applied on the substrate as a pattern, as
shown in FIGS. 6 and 7. Subsequently, the substrate was heated at
60.degree. C. on a hot plate to remove the solvent, and thereby
yielded a green light-emitting layer 18.
[0088] Cathodes were formed by vapor deposition. The resulting
article was ultimately sealed with an epoxy resin, and thereby
yielded an element (1).
[0089] An element (2) was prepared in the same manner as above,
except that a light-emitting layer composition having the same
formula shown in Table 1 except for containing no
2,3-dihydrobenzofuran was prepared and was used.
[0090] FIGS. 8 and 9 are sectional views of the organic EL thin
films.
[0091] The film thicknesses of the prepared thin films at the
center and at the edge were measured with a contact
film-thicknessmeter. When the difference in film thickness between
the center and the edge in the element (1) is defined as x (FIG. 8)
and that in the element (2) is defined as y (FIG. 9), the
relationship between x and y is:
x<y,
[0092] indicating that the formed film in the element (1) could
have a very uniform film thickness.
[0093] FIG. 10 is a graph that shows comparisons in
voltage-luminance characteristic between the elements (1) and
(2).
[0094] The element (1) showed higher luminance and more uniform
light emission than the element (2) at the same voltage, indicating
that the element (1) has satisfactory light emitting
characteristics.
EXAMPLE 3
[0095] A substrate having a multilayer structure including an ITO
electrode, a SiO film and a polyimide film, each having a
predetermined shape of an opening, was prepared, and a hole
injection-transportation layer was applied thereto in the same
manner as in Example 2. Next, a green light-emitting layer
composition (having the formula shown in Table 1) was then applied
onto the substrate, and immediately after the application, the
substrate was heated at 60.degree. C., while the solvent under a
reduced pressure (2 mm-Hg) was removed, and thereby a green
light-emitting layer was yielded. Subsequently, an element (3) was
prepared under the same conditions as in Example 2, except for the
drying condition, and the voltage-luminance characteristic of the
element (3) was measured. The same result as in Example 2 was
obtained.
EXAMPLE 4
[0096] A substrate having a multilayer structure including an ITO
electrode, a SiO film and a polyimide film, each having a
predetermined shape of an opening, was prepared, and a hole
injection-transportation layer (having the formula shown in Table
5) was applied thereto in the same manner as in Example 2.
Subsequently, 15 pl of a blue light-emitting layer composition
having the formula shown in Table 2 was discharged from a head of
an ink-jet printing device and was applied onto the substrate as a
pattern. Next, the substrate was heated at 60.degree. C. on a hot
plate to remove the solvent, and thereby yielded a blue
light-emitting layer.
[0097] Next, cathodes were formed and sealing was performed in the
same manner and condition as in Example 2, and thereby yielded an
element (4).
[0098] As a comparative example, an element (5) was prepared under
the same condition as above, except that a light-emitting layer
composition having the same formula shown in Table 2, except for
containing no 2,3-dihydrobenzofuran, was prepared and was used.
[0099] The voltage-luminance characteristics of the elements (4)
and (5) were compared, and the element (4) using a composition
containing 2,3-dihydrobenzofuran showed more uniform and higher
luminance, as in Example 2.
[0100] FIG. 11 is a graph that shows a comparison in
voltage-current characteristic between the element (4) and the
element (5).
[0101] The element (4) exhibited a lower amount of current than the
element (5), and was an excellent element with high efficiency.
EXAMPLE 5
[0102] A substrate having a multilayer structure including an ITO
electrode, a SiO2 film and a polyimide film, each having a
predetermined shape of an opening, was prepared, and a hole
injection-transportation layer (having the formula shown in Table
5) was applied thereto in the same manner as in Example 2.
Subsequently, 15 pl of a blue light-emitting layer composition
having the formula shown in Table 2 was discharged from a head of
an ink-jet printing device, and was applied onto the substrate as a
pattern. Next, the substrate was heated at 60.degree. C. on a hot
plate to remove the solvent, and thereby yielded a red
light-emitting layer.
[0103] Next, cathodes were formed and sealing was performed in the
same manner and condition as in Example 2, and thereby yielded an
element (6).
[0104] As a comparative example, an element (7) was prepared under
the same condition as above, except that a light-emitting layer
composition having the same formula shown in Table 3, except that
it contained no 2,3-dihydrobenzofuran, was prepared and was
used.
[0105] The voltage-luminance characteristics of the elements (6)
and (7) were compared, and the element (6) using a composition
containing 2,3-dihydrobenzofuran showed more uniform and higher
luminance, as in Examples 2 and 4.
[0106] By separately patterning each of the three compositions
shown in the examples according to the ink-jet process, a
high-luminance color organic EL element can be prepared. In
addition, by using the organic EL layer formed with the use of the
compositions, a color organic EL display device having excellent
luminance can be produced.
[0107] Next, electronic apparatus according to the present
invention will be illustrated. The electronic apparatus of the
present invention use the organic EL panel (the color organic EL
display device) as a display.
[0108] FIG. 12(a) is a perspective view showing an example of
mobile phones. In FIG. 12(a), a main body 500 of the mobile phone
includes a display device (a display) 501 including the organic EL
panel.
[0109] FIG. 12(b) is a perspective view showing an example of
portable information processing devices, such as word processors
and personal computers. In FIG. 12(b), an information processing
device 600 includes an input unit 601, such as a key board, an
information processing main body 603, and a display device (a
display) 602 including the organic EL panel.
[0110] FIG. 12(c) is a perspective view showing an example of
wristwatch-type electronic apparatus. In FIG. 12(c), a watch main
body 700 includes a display device (a display) 701 including the
organic EL panel.
[0111] The electronic apparatus shown in FIGS. 12(a) to 12(c) use
the organic EL panel as a display device (display), and are
satisfactory apparatus including the organic EL element (functional
element) including a uniform and homogenous thin film.
[0112] As is described above, the compositions provided by the
present invention can prevent or reduce clogging on discharge or
curving of the discharged compositions, and can stably be
discharged upon the application of the compositions by the ink-jet
process. In addition, the methods for producing a film provided by
the present invention can form a uniform and homogenous thin film
using the compositions, and can produce functional elements,
especially organic EL elements, as well as organic EL display
devices and other electro-optical devices and various types of
electronic apparatus.
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